Thermophysical Properties Of Mixtures Research Articles

Thermophysical Properties of Mixtures of 2-Ethylhexanoic Acid and p-Xylene

Thermophysical Properties of Mixtures of 2-Ethylhexanoic Acid and <i>p</i>-Xylene

Thermophysical Properties of Mixtures of 2-Ethylhexanoic Acid and Ethanol

Mixtures of 2-ethylhexanoic acid (EHA) and ethanol are common solvents for precursor solutions in spray flame synthesis for the production of nanoparticles, however, no thermophysical data are available in the literature for these mixtures. Therefore, in this work, the density, viscosity, thermal conductivity, isobaric heat capacity, and self-diffusion coefficients of mixtures of EHA and ethanol were measured at atmospheric pressure and temperatures between 293.15 and 333.15 K. Additionally, isobaric vapor-liquid equilibria of the system were measured at pressures between 20 and 80 kPa. Empirical models were parametrized and are provided for all measured properties for convenient use in spray flame synthesis process simulations and related applications.

Finite Element Simulations of Fluids Leakage through the Faulted Reservoir

Carbon dioxide (CO2) capture and storage (CCS) in geological formation as a supercritical fluid is a viable option to reduce anthropogenic greenhouse gas emissions. Due to the density difference between CO2 and formation fluid, CO2 shows a buoyant tendency. Thereby, if CO2 migrates towards the fault in a compromised faulted reservoir, it may escape the storage reservoir. Therefore, it is essential to predict fluids leakage through the faulted reservoir into the aquifer, associated pressure development, and fluids properties over time to assess associated risk and quantification of leakage. We present finite element simulations of miscible fluids flow through the faulted reservoir to elucidate this behavior. There are very few attempts to model multicomponent fluids non-isothermal model during phase change including the Equation of State (EoS) which we addressed by coupling the mass balance equation of fluids, the fractional mass transport, and the energy balance equation. To obtain fluids mixture thermo-physical properties, we used the Peng-Robinson EoS. For validation of the coupled formulation, we compared the simulation results with Ketzin Pilot project field monitoring data, which shows good agreement. A faulted reservoir comprised of five layers is used to investigate fluids leakage through a compromised reservoir. These layers are a CO2 storage reservoir, overlain by alternating caprocks and aquifers. We also considered three different CO2 injection rates to study the injection rate effect to assess the pressure buildup during injection process. We present the thermal effect by comparing the isothermal and the non-isothermal conditions. For the latter case, we assumed three different thermal gradients. Additionally, to assess the fault aperture effect, we studied three different apertures. We observed that developed pressure and fluids properties have effects on injection rates, temperature gradient, and fault aperture. Additionally, such responses in the near-field and the far-field from the injection well are critical to assess the risk, which we discussed in this paper.

Speed of sound measurement and mixing-rule evaluation of (n-butanol + n-heptane) binary mixtures

The speed of sound of the (n-butanol + n-heptane) mixtures was measured by the Rayleigh-Brillouin light scattering method at temperatures ranging from 298.05 to 618.29 K and pressures up to 9.0 MPa. The relative expanded uncertainty of the speed of sound experimental system is 1.2% (coverage factor k = 2). The mixing effects were analyzed from molecular interactions: the trend that speed of sound rises first and then decreases with the n-butanol concentration mainly depends on the rupture of alkanol structures and the molecular association, respectively. Lacking other thermophysical properties of mixtures at high temperature and pressure, six classical speed-of-sound mixing rules only based on pure component properties were evaluated by experimental data, including Wood, Nomoto, Van Dael, Impedance dependence relations, and Time-average model and Volume-average model. It was found that the estimates by Wood’s relation (recognized as Junjie’s relation) agree best with experimental data. The applicability of mixing rules was further evaluated by 21 mixtures of (n-alkanol + n-alkane), where Wood’s relation still obtains great accuracy (average of rRMSDs = 0.91% and maximum = 1.84%). For these (n-alkanol + n-alkane) mixtures of weak interaction, Wood’s relation is expected to give reliable estimates for the under a wide temperature and pressure range, for just insignificant volume change being ignored.

Effects of binary hybrid nanofluid on heat transfer and fluid flow in a triangular-corrugated channel: An experimental and numerical study

The flow and heat transfer over a modulated surface in the form of triangular protrusions using MWCNTs-TiO2 nanohybrids were investigated, and its results are detailed in this paper. The nanomaterials were functionalized and prepared at weight concentrations of 0.025%-wt., 0.05%-wt., 0.075%-wt., and 0.1%-wt., then had its morphology elucidated using the high-resolution transmission electron microscopy (HR-TEM), field emission transmission electron microscopy (FE-SEM), and Energy Dispersive X-Ray Analysis (EDX). The mixture's thermophysical properties at 303 K were determined and utilized in the investigation's numerical aspect. A steady-state 2D analysis of flow over a modulated surface was solved in ANSYS-FLUENT with turbulent flow at 5000 ≤ Re ≤ 15,000. The model was validated using the Dittus-Boelter Eq., and its average error was 9.840%. The heat transfer was enhanced by 13.181%, 18.056%, 22.033% and 26.107% for nanoparticles' weight concentrations of 0.025%-wt., 0.05%-wt., 0.075%-wt., and 0.1%-wt., respectively. The water flow and MWCNTs-TiO2 nanohybrids' turbulent kinetic energy, pressure, velocity, turbulence intensity contours, and velocity vectors were determined, and correlations were formed from the results to predict the average Nusselt number for the DW and MWCNTs-TiO2 as a function of the nanoparticles' weight concentrations.

Thermophysical Properties of Mixtures of Thorium and Uranium Nitride

The miscibility, lattice parameter, and thermophysical properties of (Th0.2U0.8)N and (Th0.5U0.5)N have been investigated. It is shown that additions of thorium nitride (ThN) to uranium nitride (UN) increases the thermophysical performance of the mixed nitride fuel form in comparison to reference UN. In the more dilute limit, additions of ThN serve as a burnable neutronic poison and reduces the change in keff over the lifecycle of the fuel. At higher concentrations, additions of ThN serve as a significant fertile source of 233U. Where appropriate, comparisons to previous work on UN + PuN mixtures are made, as this is a comparable fuel form for potential fast reactor concepts, and a suitable point of contrast in the possible design space afforded by mixed (ThxU1 − x)N fuel forms. The data from this work are the input parameters for finite element modeling of the temperature distribution in a compact reactor. The results of modeling and simulation of this core design are shown for the case of steady-state operation and during double, adjacent heat pipe failure.

Numerical investigations on flow boiling heat transfer of ammonia water binary solution (NH3/H2O) in a horizontal microchannel

The flow boiling heat transfer characteristics of NH3/H2O mixture in a 2D single horizontal microchannel (0.4 mm width × 6 mm length) were investigated by Computational Fluid Dynamics (CFD) method. The multiphase VOF model and modified phase change Lee method were adopted to address the non-isothermal phase change process of the flowing zeotropic NH3/H2O mixture, while the variations of the binary mixture thermophysical properties were also taken into account. The effects of mass flux (46~552 kg/(m2∙K)), inlet NH3 concentration (0-35% by mole) and heating wall temperature (20.5~70 ∘C) on the overall and local flow boiling heat transfer performance have been comparatively evaluated under constant heating wall temperatures. According to the numerical results, the heat dissipation rate of NH3/H2O mixture flow boiling could reach up to 1.41 MW/m2 at a mass flux of 552 kg/(m2∙s), which was 2.05 times of water single-phase flow cooling under a same constant heating wall temperature of 50 ∘C. It was also revealed that, for NH3/H2O mixture flow boiling in the microchannel, there was a threshold of inlet NH3 concentration to maintain a certain level of heat dissipation rate at a given mass flow rate and further increasing the inlet NH3 concentration would no longer benefit the heat dissipation process. Furthermore, there were no local dry-outs found throughout the whole microchannel length under all the simulation conditions in this study, which could be attributed to the unique flow boiling behaviors of zeotropic NH3/H2O mixture. Therefore, it should be noticed that NH3/H2O mixture, under certain conditions, could be a good alternative coolant for preventing local dry-outs and maintaining a certain functional temperature of electronic components.

Experimental Data of Thermophysical Properties of Mixtures of Oxygenated Additives + Hydrocarbon in Fuels and Biofuels: Application of Perturbed Chain-Statistical Associating Fluid and Peng–Robinson Equations of State

Experimental data of excess enthalpy, (HE), density, (ρ), speed of sound, (u), and the refractive index, (nD), are reported in this work for ternary and binary mixtures composed of diethylene glyco...

Thermophysical Properties of Mixtures of 1-Ethyl-3-methylimidazolium Methylsulfate or 1-Ethyl-3-methylimidazolium Thiocyanate with Alcohols

In the present paper, densities, speeds of sound, and viscosities of four binary mixtures containing the ionic liquids 1-ethyl-3-methylimidazolium methylsulfate and 1-ethyl-3-methylimidazolium thio...

Sand-sodium-silicate mixtures structured in steam-microwave environment effective values of thermo-physical properties

Purpose. Sand-sodium-silicate mixtures, structured by steam-microwave solidification, thermo-physical properties integral-effective values during Al-Mg alloy and graphite cast iron pouring determination. Sand-sodium-silicate mixture apparent density changing according to quartz sand, cladded with sodium silicate solute, fractional composition and its influence on BrA9Zh3L bronze microstructure establishment. Methodology. Quartz sand with 0.23 mm average particle size, sodium silicate solute, aluminum alloy with 8.5% Mg, flake graphite cast iron SCh200 (DSTU 8833:2019), bronze BrA9Zh3L (GOST 493-79) were used. Mixtures structuring was carried out in 700 W magnetron power microwave furnace. Sand-sodium-silicate mixture thermo-physical properties integral-effective values were calculated by G.A.Anisovich method, using castings results and molds thermography. Structured mixtures apparent density was determined on samples 50 120 mm dimension. Metallographic studies were realized using Neophot-21 optical microscope. Findings. It was found that with sodium silicate solute, used for sand cladding, amount increasing from 0.5 to 3% mold material apparent density decreases and thermal activity lowers. This leads to castings grains size increasing. Mixture sodium silicate solute content was recommended limiting 1.5% for fine-grained microstructure castings obtaining and cladded sand using, which particles pass through mesh side less 0.315 mm sieve. Sands with sodium silicate solute content more than 1.5%, which dont pass through sieve 0.4 mm mesh side, were recommended as casting molds heat-insulating material using. Originality. For the first time, when aluminum-magnesium alloy and graphite cast iron pouring, quartz sand cladded with sodium silicate solute in amount from 0.5 to 3.0% (weight, over 100% quartz sand), steam-microwave radiation structured, thermo-physical properties integral-effective values were determined. Practical value. Data obtained using will improve castings solidification time and rate analytical calculations accuracy, forecast level and residual stresses sign in them, shrinkage defects locations. This will reduce casting technology developing time and costs and castings manufacturability.

Measurements of Density and Sound Speed in Mixtures Relevant to Supercritical CO2 Cycles

Abstract The objective of this research is to validate properties of mixtures relevant to supercritical carbon dioxide (sCO2) power cycles. Direct-fired sCO2 cycles are a promising technology for the future power generation systems. The working fluid of sCO2 cycles will be near and above critical point of CO2. One of the challenges is that the simulation of mixtures should consider real gas behavior. Expected operating conditions of Allam cycles reach up to 300 bar and 1000 °C. Characterizing the mixtures at the extreme conditions is an important issue in current researches and industrial applications. Thermophysical properties of mixtures may be beyond the valid range of the widely used database such as NIST REFPROP. Experimental data of mixture properties in the literature are limited which is necessary to develop high-fidelity design tools for sCO2 power cycles. We measured the density and sound speed of several multi-component mixtures. A temperature-controlled high-pressure test cell was used for the density measurements. Sound speed was measured by resonant frequency detection using an external speaker and a piezoelectric pressure sensor. Mixtures studied in this work include carbon dioxide, methane, oxygen, and water vapor. Properties of pure CO2 were measured to show the validity of our technique. Compositions were selected to be close to frozen mixtures at the inlet, mid-progress, and exhaust conditions of a model sCO2 combustor in the previous numerical simulation work. Corresponding reaction progress variables (RPV) were RPV = 0, 0.5, and 1. Temperature and pressure conditions of experiments are 310–450 K and 0–150 bar. In our study, density and sound speed from the NIST REFPROP database agree with experimental measurements within the range of our measurement uncertainties.

Heat transfer characteristics of plug-in oscillating heat pipe with binary-fluid mixtures for electric vehicle battery thermal management

The development of highly-efficient, cost-effective, and reliable cooling schemes of electric vehicle (EV) battery is still a big challenge for massive commercialization of EVs. In this work, a proof-of-concept plug-in oscillating heat pipe (OHP) with flat-plate evaporator and tube condenser has been developed and experimentally tested for the potential applications in EV battery thermal management. Pure water, ethanol, and binary-fluid mixtures of them at different mixing ratios (MRs) ranging from 1:1 to 4:1 were used at volumetric filling ratios (FRs) of 30%, 40% and 50%. Owing to the zeotropic properties in phase transition and the complex molecular interactions between the ethanol component and water component, the OHP charged with ethanol-water mixtures exhibited better start-up and heat transfer performance. The average battery pack temperature could be controlled below 46.5 °C under the power input of 56 W. Besides, well-satisfied temperature uniformity was achieved on the battery module and the maximum temperature differences were mostly in the range of 1–2 °C. The complementary features for ethanol-water mixture thermo-physical properties and temperature/concentration gradients induced mass transport account for the OHP performance improvement. The novel plug-in OHP associated with desirable heat transfer performance provides a promising candidate for battery thermal management system.

Quasi dimensional numerical investigation of syngas fuelled engine operation: MBT operation and parametric sensitivity analysis

The formulation, validation and application of a thermodynamic quasi dimensional SI engine simulation model for syngas fuelled operation is reported. The QD approach establishes the dependence of turbulent combustion on mixture thermo-physical properties and fluid domain average turbulent parameters, eliminating the need for domain discretization (unlike in multi-dimensional models). Turbulent combustion is formulated along the Eddy Entrainment Laminar Burn-up concept (Williams-Klimov criterion) with non-linear dependence of mixture burn rate on local laminar flame speed and turbulent intensity. Simulations are reported for syngas fuelled operation of a six cylinder engine and compared with experimental pressure and heat release traces. Maximum brake torque stoichiometric operation pressure and heat release simulation traces evolve closely with corresponding experimental traces. The simulation peak pressure and IMEP deviations remain within 5% and 2% of experimental traces respectively while the position of peak pressure overlaps within ±0.5deg. Parametric sensitivity analysis for load, mixture quality and ignition timing are also addressed. Overall, the simulation results are in accordance within 5% of experimental results as long as the parametric variations are within the regimes of tuning of empirical correlations. In general, the versatility and robustness of quasi dimensional approach to simulate non-regular bio-derived alternative fuels is established.

Thermo-physical properties of water and ethylene glycol mixture based SiC nanofluids: An experimental investigation

The mixture of water and ethylene glycol (EG) is a kind of traditional heat transfer fluids commonly used in many energy systems to retain the good heating (or cooling) ability of water, as well as broadening the operating temperature range for energy applications. Therefore, the enhancement of water/EG mixture thermo-physical properties by using nanoparticles would be beneficial for the performance of the energy systems. With the purpose of filling the research gap in the literatures, this paper presents experimental data of thermal conductivity and viscosity properties of water/EG-based SiC nanofluids. It was found that the thermal conductivity of nanofluids increased with the volume fraction, and the highest thermal conductivity enhancement was found to be 33.84% for 1.0vol% nanofluid at 20°C. The prepared SiC nanofluids behaved Newtonian behavior and the viscosities decreased with the increasing temperature. In addition, the heat transfer benefits suggested that the water/EG-based SiC nanofluids had potential applications for energy systems, which indicated promising capability of this kind of nanofluids for further heat transfer characteristics investigation.

Measurement and Prediction of Volumetric Properties for Undersaturated Athabasca Bitumen

The application of solvent injection for heavy oil and bitumen recovery processes requires the predictions of the performance for a field-scale design. This directly depends upon the variation of oil properties by solvent dilution. Thus, the comparison and evaluation of the solvent effects on the density and viscosity of oil are crucial. In this study, a constant number of solvent moles is dissolved in 1 mol of bitumen at a constant temperature and pressure and the thermophysical properties of mixtures are measured. Different solvents, methane, ethane, propane, butane, and carbon dioxide, are considered for the measurements. The measurements are taken at temperatures varying from 323 to 463 K, pressures of 4, 6, 8, and 10 MPa, and mixtures with different mole percentages of the solvents (5, 10, and 15). The results indicate that, at a constant temperature, pressure, and solvent mole fraction, the undersaturated carbon dioxide/bitumen mixture has the highest density and the undersaturated butane/bitumen mixture has the lowest density. Among the hydrocarbon gases, a general slight decreasing trend of undersaturated bitumen density with carbon number is observed. Finally, the mixture densities are predicted with an effective liquid density approach with a maximum average absolute relative deviation (AARD) of 0.17%.

Viscosity Measurements and Data Correlation for Two Synthetic Natural Gas Mixtures

Viscosity is among the most relevant properties required for the reliable and economic design of natural gas processing and transport units. However, the available viscosity data covering wide pressure and temperature ranges are scarce. This worldwide research project has a goal of producing accurate thermophysical properties for synthetic natural gas mixtures in a systematic manner using state-of-the-art techniques. The main purpose of the work is to analyze the effect of different compounds on mixture thermophysical properties and the validity of available predictive models. In this work, the viscosity measurements for the first two studied samples, QNG-S1 and QNG-S2, cover the temperature range (250 to 450) K and pressure range (10 to 65) MPa. Experimental measurements utilized an electromagnetic piston viscometer with a comparison to available reference data for pure methane. Using the reported results to probe the predictive ability of several theoretical models leads to unsatisfactory results. This ...

Phase equilibrium and thermophysical properties of mixtures containing a cyclic ether and 1-chloropropane

The phase equilibrium, at T = 298.15 and 313.15 K and several thermophysical properties (density, sound velocity, refractive index) at T = 283.15, 298.15 and 313.5 K of mixtures formed by a cyclic ether (tetrahydropyran, tetrahydrofuran) and 1-chloropropane has been studied. Excess Gibbs functions, excess volumes, excess isentropic compressibilities and refractive index deviations have been obtained from the experimental data. Both the molecular characteristics of the pure compounds and the molecular interactions in the mixing process have been used to analyse the results. The SAFT-VR approach has been applied without adjustable parameter to predict the phase behaviour at isothermal conditions of the mixtures. Results have been analysed and compared to those obtained in previous studies.

Interaction Effects During Combustion of Linear Arrays of Gaseous Fuel Pockets

The numerical solution for the combustion of an infinite linear array of dense fuel gas pockets in a quiescent ambient is discussed in the present work. Fuel mass, flame, and gas pocket shape behaviors are analyzed in order to quantify the interference effects. The combustion process is considered isobaric. The model is based on mass, momentum, energy, and species conservation equations and considers the simple chemical reaction mechanism and ideal gas behavior. Coupling potentials are used in the solution of the energy and species conservations equations. The thermophysical properties, except the density, are assumed constant. The finite-volume method is used for the numerical solution, using a generalized system of coordinates and a nonstaggered grid. The SIMPLEC algorithm is applied to solve the modified pressure-velocity coupling. The flame and gas pocket morphological evolutions as well as the transient fuel consumption and the flame position behaviors are presented. The effects of the initial fuel and oxidant temperatures, of the interpocket distance, of the stoichiometric condition, of the heat of reaction, and of the mixture thermophysical properties on the combustion process are considered. Results show that the interactive effects on gas pocket linear array combustion are relevant only for small interpocket distances. Results also show flame shape temporal evolutions that indicate an oscillatory behavior dependent on the gas pocket burning conditions.

The influence of binary mixture thermophysical properties in the analysis of heat and mass transfer processes in solar distillation systems

Although a substantial amount of research work has already been devoted to various aspects of modeling the convective and mass transport processes in solar distillation systems, it appears that the role of thermophysical and transport properties of the working medium and their effect on the thermal behavior and performance analysis of such systems has been left almost completely unnoticed. The working medium in these systems, which is a binary mixture of water vapor and dry air in equilibrium, appears to exhibit a completely different set of properties than dry air, especially at saturation conditions and at the higher region of the solar still operational temperature range. An analysis is presented aiming to signify the effect of binary mixture thermophysical properties on the transport processes and the associated quantities and evaluate the thermophysical properties of the working medium in these systems, based on contemporary data for dry air and water vapor. The derived results, in the form of convenient algebraic correlations, are employed to investigate the effect of using the appropriate thermophysical properties on the calculation of the convective heat and mass transfer, as well as the distillate mass flow rates. According to the results from the present investigation, although the use of improper dry air data leads to a significant overestimation of the convective heat transfer coefficient, the errors associated with the use of improper dry air properties is a moderate overestimation of distillate output which is estimated to be up to 10% for maximum average still temperatures of 100 °C.

Thermophysical Properties of Mixtures of Tetrahydropyran with Chlorobutanes

Densities and absolute viscosities for the binary mixtures containing tetrahydropyran and isomeric chlorobutanes have been determined at 298.15 and 313.15 K at atmospheric pressure. From the densities, excess molar volumes were calculated. On the other hand, excess volumes and absolute viscosities have been correlated using the Peng–Robinson–Stryjek–Vera (PRSV) equation of state and the Lee model, respectively.